What Is a Design Pattern and Why Should We Use It?
Introduction π€π§ π‘
I often found myself asking: What is a design pattern, and why should I use it?
Although my professor explained that design patterns make code more readable, cleaner, and easier to maintain, the concept still felt abstract to me. I understood the words, but not the real value behind them.
My confusion started to clear after reading a quote by Christopher Alexander, the architect who introduced the idea of design patterns.
“Each pattern describes a problem which occurs over and over again in our environment, and then describes the core of the solution to that problem, in such a way that you can use this solution a million times over, without ever doing it the same way twice.”
This quote helped me realize that design patterns are not about copying code — they are about reusing ideas and solutions.
Who Created Design Patterns?
The concept of design patterns was first introduced in 1977 by Christopher Alexander, an architect. He used patterns to describe recurring problems and solutions in building architecture.
Later, in 1995, design patterns were adapted for software development by four software engineers:
Erich Gamma
Richard Helm
Ralph Johnson
John Vlissides
They are famously known as the Gang of Four (GoF) and authored the book:
Design Patterns: Elements of Reusable Object-Oriented Software
This book introduced 23 classic design patterns for object-oriented software design.
My Definition of a Design Pattern
A design pattern can be defined as a reusable blueprint that provides a proven solution to common problems in software development.
Design patterns do not fix bugs or syntax errors. Instead, they:
Provide a clear structure for your code
Improve readability
Encourage reusability
Make code easier to maintain and extend
Why Should We Use Design Patterns?
In real-world projects, especially large ones, developers may write hundreds or thousands of classes. When working in a team, it is essential that everyone can understand and modify each other’s code.
Without design patterns:
Code often becomes tightly coupled
Small changes may require updates in many places
Maintenance becomes difficult and time-consuming
Design patterns help reduce these problems by promoting loose coupling and clear responsibilities between components.
What Happens If We Do Not Use Design Patterns?
Not using design patterns does not automatically make your program wrong, but it can:
Increase complexity
Reduce code reusability
Slow down development over time
Make maintenance harder, especially in team projects
As stated in the GoF book:
“Designing object-oriented software is hard, and designing reusable object-oriented software is even harder.”
I would add:
“Fixing a bug and later forgetting how you fixed it is even harder.”
Design Patterns in Modern Development
Today, many programming languages and frameworks already follow specific design patterns internally. This means developers often use design patterns without realizing it.
However, understanding design patterns helps you:
Understand frameworks better
Write cleaner custom solutions
Design scalable systems
This is especially useful when working with languages like Python, Java, or PHP, where design patterns are frequently applied in larger or corporate projects.
Design Patterns and Object-Oriented Programming
In Object-Oriented Programming (OOP), design patterns help organize:
Object creation
Object relationships
Object behavior
Based on system requirements, design patterns are generally classified into three categories:
Creational Patterns
Structural Patterns
Behavioral Patterns
What’s Next?
In the next post, I will discuss the characteristics of each design pattern category and explain how to apply them in real projects.
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